PROJECT SUMMARY Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world, and results from inappropriate angiogenesis in the eye. As a result of this mechanism, anti-angiogenic drugs such as anti- vascular endothelial growth factor (VEGF) agents have become the preferred treatment for late-stage, or `wet', AMD. However, these drugs are accompanied by serious risks as they are injected repeatedly into the eye and over 50% of patients still experience vision loss. Unfortunately, the development of more effective therapies has been hampered by limited insight into the molecular mechanisms that promote angiogenesis in the retina. We hypothesize that the combined changes in the extracellular matrix (ECM) and retinal pigment epithelial (RPE) phenotype control angiogenesis in wet AMD. To test this, we propose to develop a tissue-engineered system that mimics several features of outer retinal anatomy and to then characterize angiogenesis in response to AMD-like changes to these features. This novel 3-D platform will allow us to uniquely address specific questions about retinal biology, yield information about the relative influences of retinal properties in regulating angiogenesis, and ultimately identify and screen new therapies for wet AMD. Aim 1: Create a tissue-engineered retinal environment to characterize the relative influences of AMD- mimicking changes on angiogenesis. We will develop a novel 3-D tissue-engineered system simulating key elements of the retinal anatomy. This system will be used to examine angiogenesis by endothelial cells (ECs) in the context of changes in the retinal microenvironment that mimic changes observed in wet AMD. Aim 2: Using a systems biology analysis, identify alternative targets or stage-specific treatments to regulate angiogenesis in AMD. We will utilize our tissue-engineered model to examine receptor activation on the ECs in response to angiogenic ligands secreted by RPE cells across different stages of angiogenesis. We will then use these experiments to construct a predictive computational model that will enable identification of individual (or combined) soluble factors that most strongly promote angiogenesis at various stages of disease. Via in silico perturbations, we will predict outcomes for inhibiting these factors/receptors, and then test these new inhibition strategies in our in vitro experimental model. The outcomes of this work will be: 1) creation of a sophisticated in vitro platform for characterizing the pathophysiology of wet AMD and relative contributions of microenvironmental factors in this process, 2) identification of novel targets and/or stage-specific treatments for wet AMD.